Experimental analysis of natural gas transport: using nanoporous ceramic cores as mimetic model for low permeability reservoirs.

Ogoun, Evans

Abstract

This research investigates the use of nanoporous ceramic cores as mimetic models for studying natural gas transport in low permeability reservoirs. Low permeability reservoirs, such as tight sands, coalbed methane and shale gas formations, present significant challenges for natural gas extraction due to their complex pore structures and limited flow characteristics. Traditional methods for studying these reservoirs, like sand pack simulations and direct core analyses, have limitations including difficulty in replicating the heterogeneity of natural rocks and high costs. Synthetic nanoporous ceramic cores may offer opportunities, but literature on their use for reservoir studies is yet scarce. This study aim to bridge this knowledge gap by adopting Flux, Permeability, Mobility and Reservoir Quality Index as objective functions to evaluate the use of nanoporous ceramic cores in describing the micro-geological characteristics of low permeability reservoirs. The research involved rigorous data mining and experimental methodologies, comprising the analysis of extensive experimental data points from numerous CH4 and CO2 permeation tests, enhancing the reliability and validity of the findings. Additionally, wide-ranging field data from reservoirs that have implemented CH4 and CO2 gas dynamics were analysed. Five distinct nanoporous ceramic core samples with varied petrophysical properties were utilised in the experimental setup. Statistical tools, including clustering, mean and coefficient of variation (CV), were employed to analyse, couple and compare the datasets from the gas experiments and field data. Machine learning techniques were used to enhance the analysis, utilising algorithms to analyse permeability, mobility, Darcy flux and reservoir quality index based on the experimental and field data. The use of machine learning models, such as linear regression, allowed for the identification of complex patterns and relationships between the variables, providing deeper insights into the gas transport mechanisms within the nanoporous ceramic cores. The correlation analysis revealed significant relationships between temperature, pressure and viscosity with permeability, mobility, Darcy flux and reservoir quality index. These relationship findings were further integrated with established theoretical and empirical research from the domains of petroleum engineering, geomechanics and hydrogeology, thus significantly bolstering the study's scientific rigour and validity. The results indicated that the nanoporous ceramic cores significantly mimic the behaviour of reservoirs, displaying analogous patterns in permeability, mobility, reservoir quality index and Darcy flux. Specifically, statistical means and cluster geometry demonstrated that CH4 exhibited higher permeability (4.62e-04 mD) and mobility (0.03 mD/cp) compared to CO2 (4.21e-04 mD and 0.02 mD/cp, respectively) in the experimental settings. These results align with the data mining analysis of field data, where mean permeability for CH4 (6.87e2 mD) is higher than that for CO2 (1.00e2 mD). Furthermore, the graphical rendering and coupling of the two datasets indicate an opportunity for the geometric transformation of the experiment to reservoir realities. Suggesting that nanoporous ceramic cores can serve as analogues for low permeability reservoir cores in natural gas transport studies, offering a cost-effective and environmentally friendly alternative to traditional coring methods, which are often expensive and environmentally intrusive. The study highlights how factors such as pressure, temperature and fluid viscosity impact gas transport in nanoporous ceramic cores and how these impacts are mirrored in the field. This aids in optimising gas injection strategies and improving overall reservoir management practices. In conclusion, this study gives credence to the use of nanoporous ceramic cores as mimetic models for low-permeability reservoirs, opening new avenues for research and technological advancements in the field. The successful application of these cores can lead to better modelling of reservoir conditions, improved extraction techniques, and enhanced reservoir management practices, resulting in cost savings, technical advantages, and reduced environmental impacts associated with traditional coring methods.

Citation

OGOUN, E. 2024. Experimental analysis of natural gas transport: using nanoporous ceramic cores as mimetic model for low permeability reservoirs. Robert Gordon University, PhD thesis. Hosted on OpenAIR [online]. Available from: https://doi.org/10.48526/rgu-wt-2795722

• Thesis Type: Thesis
• Deposit Date: Apr 18, 2025
• Publicly Available Date: Apr 18, 2025
• DOI: https://doi.org/10.48526/rgu-wt-2795722
• Keywords: Nanoporous ceramic cores; Low permeability; Natural gas transport; Gas reservoirs; Darcy's equation; Darcy's law
• Public URL: https://rgu-repository.worktribe.com/output/2795722
• Award Date: Sep 30, 2024